Method to reduce data rates and power consumption using device based attitude quaternion generation

Abstract

A method includes generating motion data by receiving a gyroscope data from a gyroscope sensor, performing integration using the gyroscope data and generating an integrated gyroscope data using a first processor. The method further includes receiving a data from one or more sensors, other than the gyroscope sensor, and performing sensor fusion using the integrated gyroscope data and the data to generate motion data using a second processor.

What we claim is: 
     
       1. A sensor device, comprising:
 a sensor package including, 
 a first silicon substrate including a three-axis microelectromechanical system (MEMS) gyroscope and a three-axis MEMS accelerometer; 
 a second silicon substrate including a first processor, the second silicon substrate connectively and electrically coupled to the first silicon substrate, the three-axis MEMS gyroscope configured to generate raw gyroscope data with a gyroscope bias, the raw gyroscope data being a measurement output from the three-axis MEMS gyroscope, the first processor configured to receive the raw gyroscope data and remove the gyroscope bias to generate an unbiased gyroscope data, and integrate the unbiased gyroscope data into a gyroscope quaternion at a first rate, 
 wherein the first silicon substrate is vertically stacked and attached to the second silicon substrate within the sensor package, 
 further wherein the sensor package is configured to transmit the integrated gyroscope data at a second rate, the second rate being lower than the first rate. 
 
     
     
       2. The sensor package of  claim 1 , wherein, the sensor package is configured to transmit the integrated gyroscope data to a second processor, wherein the second processor resides in the second silicon substrate. 
     
     
       3. The sensor package of  claim 2 , wherein the second processor is an application processor. 
     
     
       4. The sensor package of  claim 2 , wherein the second processor is a Micro Controller Unit (MCU). 
     
     
       5. The sensor package of  claim 1 , wherein the higher of the first and second rates is 200 Hertz or higher. 
     
     
       6. The sensor package of  claim 1 , wherein the first silicon substrate and the second silicon substrate are coupled to each other through wafer bonding. 
     
     
       7. The sensor package of  claim 1 , wherein the sensor package is configured to transmit the integrated gyroscope data and the three-axis MEMS accelerometer data to a second processor formed on the second silicone substrate for fusion of the integrated gyroscope data and the three-axis MEMS accelerometer data by the second processor. 
     
     
       8. The sensor package of  claim 1 , wherein the integrated gyroscope data is transmitted for use by a sensor fusion. 
     
     
       9. The sensor package of  claim 1 , wherein an estimated gyroscope data is a derivative of the integrated gyroscope data relative to the change in time. 
     
     
       10. The sensor package of  claim 9 , wherein the gyroscope bias is calculated based on the estimated gyroscope data relative to the change in time. 
     
     
       11. The sensor package of  claim 1 , wherein the integration of the raw gyroscope data is performed using a curve-fit. 
     
     
       12. The sensor package of  claim 1 , wherein the second substrate further includes a register configured to store the integrated gyroscope data. 
     
     
       13. The sensor package of  claim 1 , wherein the integration of the raw gyroscope data is performed using vector addition, a quaternion multiplication and vector normalization. 
     
     
       14. The sensor package of  claim 1 , wherein the integration of the raw gyroscope data is performed using cosine and sine of the raw gyroscope data. 
     
     
       15. The sensor package of  claim 1 , wherein the integration of the raw gyroscope data is performed when an angular velocity is constant for a predetermined period of time. 
     
     
       16. The sensor package of  claim 1 , wherein the raw gyroscope data is received by the first processer directly from the three-axis MEMS gyroscope. 
     
     
       17. A sensor device comprising:
 a Motion Processing Unit (MPU) including,
 a three-axis microelectromechanical system (MEMS) gyroscope configured to generate raw gyroscope data, the raw gyroscope data being a measurement output from the three-axis MEMS gyroscope and having a gyroscope bias; 
 a three-axis MEMS accelerometer configured to generate raw accelerometer data; 
 an integration device, 
 
 wherein the three-axis MEMS accelerometer, three-axis MEMS gyroscope and integration device are formed on a first silicon substrate, 
 a second silicon substrate including a first processor electrically coupled to the first silicon substrate, 
 wherein the first processor is configured to calculate the gyroscope bias and to remove the calculated gyroscope bias from the raw gyroscope data to generate an unbiased gyroscope data, 
 further wherein the integration device is responsive to the unbiased gyroscope data and configured to integrate the unbiased gyroscope data into a gyroscope quaternion at an integration rate and to transmit the integrated gyroscope data at a rate lower than the integration rate, 
 further wherein, the raw accelerometer data and the unbiased gyroscope data are employed with raw compass data from a compass formed on the second silicon substrate, 
 further wherein the first silicon substrate is vertically stacked and attached to the second silicon substrate.